Electromagnetic Mechanism and Buffering Performance Analysis of Linear Tubular Electromagnetic Source Eddy Current Dampers

This study derives a theoretical formula for calculating the damping force of the electromagnetic source eddy current damper (ES-ECD) based on the magnetic vector potential form of Maxwell’s equations and layer theory. The accuracy of the formula is validated through finite element modeling (FEM) and a static magnetic field test, with a maximum error of less than 3% in the damping force–velocity curve. A comparison with the permanent-magnet source eddy current damper (PS-ECD) reveals the electromagnetic evolution mechanism underlying the damping force–velocity relationship of the ES-ECD. The results indicate that the ES-ECD exhibits a lower critical velocity and enhanced nonlinearity in the damping force beyond the critical point, attributed to the intensified opposing magnetic field generated in the time-varying field. The axial pole-pitch ratio, $\alpha $ , significantly influences the nonlinear characteristics of the ES-ECD, with the damping force per unit ampere-turn reaching its maximum at $\alpha =0.65$ . The nonlinear characteristics of the ES-ECD make the damping coefficient more sensitive to variations in conductor thickness and air gap. At low velocities, the higher nonlinear damping coefficient broadens the optimal parameter range of traditional eddy current dampers (ECDs), offering enhanced versatility. Through numerical simulation of the dynamic response characteristics of the impact buffering system for the falling mass block, it has been verified that the ES-ECD can achieve up to a 20.6% improvement in buffering performance compared to the PS-ECD, effectively absorbing the system’s impact energy and achieving swift vibration attenuation.